Chemical-mechanical polishing (xe2x80x9cCMPxe2x80x9d) is a commonly used technique for planarizing material on a semiconductor wafer. CMP often requires introduction of a polishing slurry as the wafer is being mechanically polished against a rotating polishing pad. Slurries typically are water based and can contain fine abrasive particles such as silica, alumina, and other abrasive materials. After CMP is complete, the wafers are exposed to cleaning chemistries to remove residual slurry and other residue in order to prepare the wafer for subsequent fabrication utilizing techniques such as etching, photolithography, ion-implantation and the like.
Cleaning chemistries may be delivered to the post-CMP wafer cleaner directly from a bulk supply of a particular fabrication facility. However, the flow of cleaning chemistry from the bulk supply may vary depending upon demands placed upon the bulk supply by other post-CMP cleaning systems.
Therefore, liquid delivery modules having a cleaning chemistry storage capacity are frequently employed to dispense cleaning chemistry for post-CMP wafer cleaning. This configuration renders the flow of cleaning chemistry to the post-CMP cleaning tool essentially independent of the flow of cleaning chemistry from the bulk supply.
Because of the need for rapid throughput of polished wafers to be cleaned, it is desirable that the liquid dispense module provide a continuous flow of cleaning chemistry, interrupted only by the transfer of a cleaned wafer out of the cleaner and the loading of the next wafer to be cleaned. In addition, due to space considerations and the need for ease of servicing, it is desirable that the liquid dispense module occupy as little space as possible, and also that the design of the liquid dispense module be relatively simple to permit ready access to various components of the device. Accordingly, new compact and simple designs for liquid delivery modules to dispense fluids utilized in semiconductor fabrication process are desirable.
The present invention relates to liquid delivery module for a semiconductor process that is compact and of simple construction. Specifically, one embodiment of a liquid delivery module in accordance with the present invention features two chambers linked to each other through a valve assembly. In a non-refill module state, the chambers are in fluid communication with each other and act as a single vessel. Positive pressure applied to the module results in the dispensing of liquid material.
When liquid material within the delivery module becomes depleted, in a refill module state the chambers are sealed off from one another to permit refilling. One chamber remains pressurized to allow the remaining material to be supplied to complete processing of the wafer. The second chamber is vented and placed into fluid communication with the material supply.
Once the level of material second chamber has been restored, and once supply of liquid material to the wafer being processed has been completed, during transfer of the processed wafer the second chamber is sealed off from the material supply, pressurized, and again placed back into fluid communication with the first chamber. This permits dispensing to continue uninterrupted with the next wafer.
One embodiment of a delivery module in accordance with the present invention comprises a vessel including a first chamber and a second chamber, the vessel configured to receive the material from a bulk supply and to receive a pressurized flow of gas from a gas source. The delivery module further comprises a valve assembly operable to selectively permit fluid communication between the first chamber and the second chamber during a non-refill module state, and to prevent fluid communication between the first chamber and the second chamber during a refill module state.
One embodiment of a method of delivering material to a semiconductor processing tool in accordance with the present invention comprises supplying a pressurized flow of an inert gas to a first chamber of a vessel containing the material, such that the material in the first chamber flows out of the first chamber to the semiconductor processing tool. In a refill state, while dispensing the material to the semiconductor processing tool from the first chamber, a second chamber of the vessel is vented and the material is supplied to the second chamber from a bulk material supply. In a non-refill state, the second chamber is sealed from the environment and placed in fluid communication with the first chamber, such that the material flows from the first chamber to the semiconductor processing tool.
These and other embodiments of the present invention, as well as its advantages and features, are described in more detail in conjunction with the text below and attached figures.